Abstract

Biochar has recently been used for recovering nutrients from waste streams including source-separated human urine. The increased consumption of pharmaceuticals has been a subject of concern as some of the compounds are not completely metabolized and consequently present in human urine. As urine contains both nutrients and pharmaceuticals, biochar applied for nutrient recovery may adsorb pharmaceuticals causing a concern on the introduction of the contaminants to the environment. This review article discusses the sorption of nutrients as well as pharmaceuticals by biochar. It reveals that biochars with different properties can be employed to separately attain nitrogen and phosphorus recovery, and removal of pharmaceuticals from source-separated urine. Production conditions including pyrolysis temperature and feedstock source are the vital aspects for delivering biochar properties that are suitable for different groups of chemical entities (nutrients versus pharmaceuticals). In addition, pharmaceutical adsorption is more favorable at lower solution pH whereas nutrient recovery is favorable at higher solution pH. If this concept of using separate biochars is employed, it will minimize the potential exposure of pharmaceuticals to the environment and humans and in the process the nutrient-rich biochar can be applied to the agrarian fields to achieve a closed-loop fertility system.

摘要

Biochar 最近被用于从废物流中回收营养物质，包括源分离的人尿。药物消费的增加一直是一个令人担忧的问题，因为一些化合物没有完全代谢，因此存在于人尿中。由于尿液中既含有营养物质又含有药物，用于营养物质回收的生物炭可能会吸附药物，从而引起人们对将污染物引入环境的担忧。这篇评论文章讨论了 biochar 对营养物质和药物的吸附。结果表明，不同性质的生物炭可分别用于氮磷回收，以及源分离尿液中药物的去除。包括热解温度和原料来源在内的生产条件是提供适用于不同化学实体组（营养素与药物）的生物炭特性的重要方面。此外，在较低的溶液 pH 值下药物吸附更有利，而在较高的溶液 pH 值下有利于养分回收。如果采用这种使用单独生物炭的概念，它将最大限度地减少药物对环境和人类的潜在暴露，在此过程中，营养丰富的生物炭可以应用于农田，以实现闭环肥力系统。在较低的溶液 pH 值下药物吸附更有利，而在较高的溶液 pH 值下有利于养分回收。如果采用这种使用单独生物炭的概念，它将最大限度地减少药物对环境和人类的潜在暴露，在此过程中，营养丰富的生物炭可以应用于农田，以实现闭环肥力系统。在较低的溶液 pH 值下药物吸附更有利，而在较高的溶液 pH 值下有利于养分回收。如果采用这种使用单独生物炭的概念，它将最大限度地减少药物对环境和人类的潜在暴露，在此过程中，营养丰富的生物炭可以应用于农田，以实现闭环肥力系统。